The Japanese invasions of Korea comprised two separate yet linked operations: an initial invasion in 1592, a brief truce in 1596, and a second invasion in 1597. The conflict ended in 1598 with the withdrawal of the Japanese forces[1][3] from the Korean Peninsula after a military stalemate[2] in Korea's southern coastal provinces.[19]

The invasions were launched by Toyotomi Hideyoshi with the intent of conquering Korea and China, which were ruled by the Joseon and Ming dynasties, respectively. Japan quickly succeeded in occupying large portions of the Korean Peninsula, but the contribution of reinforcements by the Ming Dynasty,[20][21][22] as well as the disruption of Japanese supply fleets along the western and southern coasts by the Joseon Navy[23][24][25][26][27] forced a withdrawal of Japanese forces from Pyongyang and the northern provinces to the south, where the Japanese continued to occupy Hanseong (present-day Seoul) and the southeastern regions. Afterwards, with guerrilla warfare waged against the Japanese by Joseon civilian militias[28] and supply difficulties hampering both sides, neither the Japanese nor the combined Ming and Joseon forces were able to mount a successful offensive or gain any additional territory, resulting in a military stalemate in the areas between Hanseong and Kaesong. The first phase of the invasion lasted from 1592 until 1596, and was followed by ultimately unsuccessful peace negotiations between Japan and the Ming between 1596 and 1597.

In 1597, Japan renewed its offensive by invading Korea a second time. The pattern of the second invasion largely mirrored that of the first. The Japanese had initial successes on land, capturing several cities and fortresses, only to be halted and forced to withdraw to the southern coastal regions of the peninsula. The pursuing Ming and Joseon forces, however, were unable to dislodge the Japanese from their remaining fortresses and entrenched positions in the southern coastal areas,[29][30][31] where both sides again became locked in a ten-month long military stalemate.

With Hideyoshi's death in 1598, limited progress on land, and continued disruption of supply lines by the Joseon navy, the Japanese forces in Korea were ordered to withdraw back to Japan by the new governing Council of Five Elders. Final peace negotiations between the parties followed afterwards and continued for several years, ultimately resulting in the normalization of relations.[32]

In Korean, the first invasion (1592–1593) is called the "Japanese (倭 |wae|) Disturbance (亂 |ran|) of Imjin" (1592 being an imjin year in the sexagenary cycle). The second invasion (1597–1598) is called the "Second War of Jeong-yu" (丁酉). Collectively, the invasions are referred to as the Imjin War.

In Chinese, the wars are referred to as the "Wanli Korean Campaign", after then reigning Chinese emperor, or the "Renchen War to Defend the Nation" (壬辰衛國戰爭), where renchen (壬辰) is the Chinese reading of imjin.

In Japanese, the war is called Bunroku no eki (文禄の役). Bunroku referring to the Japanese era under the Emperor Go-Yōzei, spanning the period from 1592 to 1596. The second invasion (1597–1598) is called "Keichō no eki" (慶長の役). During the Edo period (17–19th centuries), the war was also called "Kara iri" (唐入り "entry into China"), because Japan's ultimate purpose at the commencement of the invasion was the conquest of Ming China, although with the reality that the conflict was largely confined to the Korean Peninsula for the duration of the war, the armies of Toyotomi Hideyoshi would alter their immediate objectives during the course of the campaign.

In 1592, with an army of approximately 158,000 troops, Toyotomi Hideyoshi launched what would end up being the first of two invasions of Korea, with the intent of conquering Joseon Korea and eventually Ming Dynasty China. Initially, the Japanese forces saw overwhelming success on land, capturing both Hanseong (present-day Seoul), the capital of Korea, and Pyongyang, and completing the occupation of large portions of the Korean Peninsula in three months. The Japanese forces, well trained, confident, and experienced after the numerous battles and conflicts of the Sengoku Period, typically held the field in most land engagements. This success on land, however, was constrained by the naval campaigns of the Korean navy which would continue to raid Japanese supply fleets in its coastal waters, hampering the Japanese advances as supply lines were disrupted along the Western Korean coast and Japanese naval reinforcements were repelled.[33][34] These trends, with some exceptions on both sides, held true throughout much of the conflict.

Under the rule of the Wanli Emperor, Ming China quickly interpreted the Japanese invasions as a challenge and threat to its tributary system.[35] The Ming's interest was also to keep the war confined to the Korean peninsula and out of its own territory (to avoid territorial destruction);[36] they entered into the conflict by dispatching reinforcements to attack from the north. In the engagements that followed, the majority of the Joseon army was focused on defending the northern provinces from Japanese offensives, while also supporting Ming army campaigns to recapture territory occupied by the Japanese. These Ming-led land campaigns, combined with the naval warfare waged by Joseon navy, eventually forced the Japanese army to withdraw from Pyongyang to the south, where the Japanese continued to occupy Hanseong and the southern regions with the exception of the southwestern Jeolla province.[20][21][22] The pursuing Ming and Joseon armies attempted to advance further into the south, but were halted by the Japanese army at the Battle of Byeokjegwan.[37][38] Subsequently, the Japanese armies launched a counterattack in an attempt to reoccupy the northern provinces but were repelled by the defending Joseon army at Haengju fortress. Additionally, Joseon's civilian-led Righteous Armies actively waged guerrilla warfare against the Japanese forces in the south, which weakened the Japanese hold in the cities they occupied.[39] Afterwards, with supply difficulties hampering both sides, neither the Japanese nor the combined Ming and Joseon forces were able to mount a successful offensive or gain any additional territory, resulting in a military stalemate in the areas between Hanseong and Kaesong. The war continued in this manner for five years, and was followed by a brief interlude between 1596 to 1597 during which Japan and the Ming engaged in ultimately unsuccessful peace talks.[40]

In 1597, Japan renewed its offensive by invading Korea a second time. The pattern of the second invasion largely mirrored that of the first. The Japanese had initial successes on land, but the contribution of the Ming forces, as well as the Joseon Navy's disruption of Japanese supply fleets resulted in a withdrawal of Japanese forces towards the coastal regions of the peninsula. The pursuing Ming and Joseon forces, however, failed to dislodge the Japanese from their fortresses and entrenched positions in the southern coastal areas[29][30][41] where both sides became locked in a ten-month long military stalemate.

With Hideyoshi's death in September 1598, limited progress on land, and continued disruption of supply lines along the western and southern coasts by the Joseon navy, the remaining Japanese forces in Korea were ordered to withdraw back to Japan by the new governing Council of Five Elders. Final peace negotiations between the parties followed afterwards and continued for several years, ultimately resulting in the normalization of relations.

In 1392, the Korean General Yi Seong-gye led a successful coup to take political power from King U of the Goryeo Dynasty. Seong-gye's followers forced to take the crown, thus founding the Joseon Dynasty.[42] In search of a justification for its rule given the lack of a royal bloodline, the new regime received recognition from China and integration into the Imperial Chinese tributary system within the context of the Mandate of Heaven.[43][44][45] Within this tributary system, China assumed the role of a "big brother," with Korea maintaining the highest position among the tributary states,[46][47] which also included countries such as the Ryukyu Kingdom, Vietnam, Thailand, Burma, and Laos,[48][49] in return for accepting the subservient tributary role of a "younger brother."[50]

In 1402, Japan under Ashikaga Yoshimitsu was conferred the title of 'King of Japan' by the Chinese emperor and through this title had similarly accepted a position in the imperial tributary system as of 1404. This relationship ended in 1549 when Japan, unlike Korea, chose to end its recognition of China's regional hegemony and cancel any further tribute missions.[51] Membership in the tributary system was a prerequisite for any economic exchange with China; in exiting the system, Japan relinquished its trade relationship with China.[52]

Unlike the situation over one thousand years earlier when the Sui and Tang Chinese dynasties had an antagonistic relationship with Goguryeo, one of the Three Kingdoms of Korea, Ming China had close trading and diplomatic relations with the Korean Joseon Dynasty, which remained integrated in the imperial tributary system, but also received tribute and trade from Japan.[53][54][55][56]

The two dynasties, Ming and Joseon (sometimes transliterated as Choson), shared much in common: both emerged during the fourteenth century after the end of Mongolian rule, embraced Confucian ideals in society, and faced similar external threats (the Jurchen raiders and the wokou (wakō) pirates).[57] Internally, both China and Korea were troubled with fights among competing political factions, which would significantly influence decisions made by the Koreans prior to the war, and those made during the war by the Chinese.[58][59] Dependence on each other for trade and also having common enemies resulted in Korea and Ming China having a friendly relationship.

The Wanli Emperor was enthroned in the year 1572, at the age of 9. For the first 10 years of his reign, the Ming was largely run by his teacher and guardian, Zhang Juzheng, who pushed through a series of reforms that revitalized the declining dynasty and made major breakthroughs in several of the key areas that had plagued the Ming, especially its financial problems. Zhang also made strong progress in defending against the Mongols of the north, and (as opposed to the corrupt practices of the past) promoted military generals, such as Li Chengliang and Qi Jiguang, based on their merits.

After Zhang Juzheng's death in 1582, the Ming court slowly began to reverse some of his reforms and the Wanli Emperor himself increasingly became disillusioned and uninterested in daily politics. During the 1590s, the Ming dynasty was still at a relatively revitalized stage.

The Ming saw a string of conflicts during this period. Aside from their endless struggle against the Mongolians, they were also dealing with a military rebellion in Ningxia just before the war broke out, along with a border war with the Burmese Taungoo dynasty that coincided with the Imjin war. Their conflicts with the wokou pirates a couple of decades earlier also gave them significant experience against the Japanese style of warfare.

Japan was by this time ending a period of internal conflict and the process of unification had been taken forward by Toyotomi Hideyoshi. Japan launched their first attack on the Korean peninsula, with the casus belli that Korea had refused to allow Japanese soldiers pass through their land to militarily confront China. This could have effectively been true since Japan was eager, for social and economic reasons, to take land on the continent and expand.

By the last decade of the 16th century, Toyotomi Hideyoshi, preeminent of the daimyō, had unified all of Japan in a brief period of peace. Since Hideyoshi came to hold power in the absence of a legitimate successor of the Minamoto lineage necessary for the Imperial Shogun commission, he sought military power to legitimize his rule and to decrease his dependence on the Imperial family.[60] It is also suggested that Hideyoshi planned an invasion of China to fulfill the dreams of his late lord Oda Nobunaga,[61] and to mitigate the possible threat of civil disorder or rebellion posed by the large number of now idle samurai and soldiers in unified Japan.[62] However, it is also quite possible that Hideyoshi might have set a more realistic goal of subjugating the smaller neighbouring states (i.e. the Ryukyus, Taiwan, and Korea), and treating the larger or more distant countries as trading partners,[60] because throughout the invasion of Korea, Hideyoshi sought for legal tally trade with China.[60] Hideyoshi's need for military supremacy as a justification for his rule which lacked Shogunal background could, on an international level, eventually translate into an order with Japan's neighbouring countries below Japan.[60] Hideyoshi was also tempted by an external conflict to prevent internal rebellion within Japan. This would keep his newly formed state united against a common enemy, and prevent the daimyos from acting on any ambitions against his rule. Fighting a war away from Japanese territory would also prevent territorial destruction, and maintain the infrastructure of the state.[63] These considerations would be consistent with the fact that Hideyoshi was not a Shogun nor had any bonds with the imperial bloodline.

The defeat of the Odawara-based Hōjō clan in 1590[64] finally brought about the second unification of Japan, and Hideyoshi began preparing for the next war. Beginning in March 1591, the Kyūshū daimyō and their labor forces constructed Nagoya Castle in Nagoya, Saga (modern-day Karatsu, not to be confused with present day Nagoya city in Aichi prefecture) as the center for the mobilization of the invasion forces.[65]

Hideyoshi planned for a possible war with Korea long before completing the unification of Japan, and made preparations on many fronts. As early 1578, Hideyoshi, then fighting under Oda Nobunaga against Mōri Terumoto for control of the Chūgoku region of Japan, informed Terumoto of Nobunaga's plan to conquer China.[66] In 1592 Hideyoshi sent a letter to the Philippines demanding tribute from the governor general and stating that Japan had already received tribute from Korea (which was a misunderstanding) and the Ryukyus.[67]

As for the military preparations, the construction of as many as 2,000 ships may have begun as early as 1586.[68] To estimate the strength of the Korean military, Hideyoshi sent an assault force of 26 ships to the southern coast of Korea in 1587.[69] On the diplomatic front, Hideyoshi began to establish friendly relations with China long before completing the unification of Japan and helped to police the trade routes against the wokou.[70]

In 1587, Hideyoshi sent his first envoy Yutani Yasuhiro,[71][72][73] to Korea, which was during the rule of King Seonjo[74] to re-establish diplomatic relations between Korea and Japan (broken since the Wokou raid in 1555),[75] which Hideyoshi hoped to use as a foundation to induce the Korean court to join Japan in a war against China.[76] Yasuhiro, with his warrior background and an attitude disdainful of the Korean officials and their customs, failed to receive the promise of future ambassadorial missions from Korea.[77]

Around May 1589, Hideyoshi's second embassy, consisting of Sō Yoshitoshi (or Yoshitomo),[78][79] Yanagawa Shigenobu,[80][81] and Buddhist monk Genso,[82] reached Korea and secured the promise of a Korean embassy to Japan in exchange for a group of Korean rebels which had taken refuge in Japan.[77]

In 1587, Hideyoshi had ordered the adopted father of Yoshitoshi and the daimyō of Tsushima, Sō Yoshishige,[72][83] to offer the Joseon Dynasty an ultimatum of submitting to Japan and participating in the conquest of China, or facing the prospect of open war with Japan. However, as Tsushima enjoyed a special trading position as the single checkpoint to Korea for all Japanese ships and had permission from Korea to trade with as many as 50 of its own vessels,[84] the Sō family had a vested interest in preventing conflict with Korea, and delayed the talks for nearly two years.[78] Even when Hideyoshi renewed his order, Sō Yoshitoshi reduced the visit to the Korean court to a campaign to better relations between the two countries. Near the end of the ambassadorial mission, Yoshitoshi presented King Seonjo a brace of peafowl and matchlock guns – the first advanced firearms to come to Korea.[85]Ryu Seong-ryong, a high-ranking scholar official, suggested that the military put the arquebus into production and use, but the Korean court failed to appreciate its merits. This lack of interest and underestimation of the power of the arquebus guns greatly contributed to the failures of the Korean army early in the war.

On April 1590, the Korean ambassadors including Hwang Yun-gil and Kim Saung-il[86] left for Kyoto, where they waited for two months while Hideyoshi was finishing his campaign against the Hojo clan.[87] Upon his return, they exchanged ceremonial gifts and delivered King Seonjo's letter to Hideyoshi.[87] Hideyoshi mistakenly assumed that the Koreans had come to pay a tributary homage to Japan. For this reason the ambassadors were not given the formal treatment that was due to diplomatic representatives. In the end, the Korean ambassadors asked for Hideyoshi to write a reply to the Korean king, for which they waited 20 days at the port of Sakai.[88] The letter, redrafted as requested by the ambassadors on the ground that it was too discourteous, invited Korea to submit to Japan and join in a war against China.[85]

Upon the ambassadors' return, the Joseon court held serious discussions concerning Japan's invitation;[89] while Hwang Yun-gil reported conflicting estimates of Japanese military strength and intentions. They nonetheless pressed that a war was imminent. Kim Saung-il claimed that Hideyoshi's letter was nothing but a bluff. Moreover, the court, aware only that Japan was in turmoil with various clan armies fighting each other, substantially underrated the combined strength and abilities of many Japanese armies at the time. Some, including King Seonjo, argued that Ming should be informed about the dealings with Japan, as failure to do so could make Ming suspect Korea's allegiance, but the court finally concluded to wait further until the appropriate course of action became definite.[90]

In the end, Hideyoshi's diplomatic negotiations did not produce the desired result with Korea. The Joseon Court approached Japan as a country inferior to Korea, and saw itself as superior according to its favored position within the Chinese tributary system. It mistakenly evaluated Hideyoshi's threats of invasions to be no better than the common wokou Japanese pirate raids.[91] The Korean court handed to Shigenobu[80] and Genso, Hideyoshi's third embassy, King Seonjo's letter rebuking Hideyoshi for challenging the Chinese tributary system. Hideyoshi replied with another letter, but since it was not presented by a diplomat in person as expected by custom, the court ignored it.[92] After this denial of his second request, Hideyoshi proceeded to launch his armies against Korea in 1592.

The two major security threats to Korea and China at the time were the Jurchens, who raided along the northern borders, and the wokou, who pillaged the coastal villages and trade ships.[93][94]

This defensive stance within an environment of relative peace pushed the Koreans to depend on the strength of their fortresses and warships. With the transmission of gunpowder and firearmstechnology from China during the Goryeo Dynasty, Korea improved upon the original Chinese firearm designs, black powder bombs and developed advanced cannon which were used with great efficiency at sea. Even though China was the main source of new military technologies in Asia, Korea was a manufacturing base of both cannon and shipbuilding during this era.[95]

Japan, on the other hand, had been in a state of civil war for over a century, which had the result of turning Japan into a very proficient warlike society. When traders from Portugal arrived in Japan and introduced arquebuses and muskets, the Japanese warlords were quick to adapt to this innovative weapon, producing en masse the Tanegashima matchlock. In the on-going civil strife, the Japanese refined the drills and tactics to make best use of the new weapon, thus giving them a great advantage over the Korean armies.

Korean cannon were not adapted for effective use on land, and firearms were of a less advanced design. The small arms carried by Japanese soldiers proved to be particularly effective during land engagements and sieges.[96] This strategic difference in weapons development and implementation contributed to the trend during the war of Japanese dominance on land and Korean dominance at sea.

As Japan had been at war since the mid-15th century, Toyotomi Hideyoshi had half a million battle-hardened soldiers at his disposal[97] to form a remarkable professional army in Asia for the invasion of Korea.[98] While Japan's chaotic state had left the Koreans with a very low estimate of Japan as a military threat,[98] there was a new sense of unity among the different political factions in Japan, as indicated by the "sword hunt" in 1588 (the confiscation of all weapons from the peasants).[99] Along with the hunt came "The Separation Edict" in 1591, which effectively put an end to all Japanese wokou piracy by prohibiting the daimyōs from supporting the pirates within their fiefs.[99] Ironically, the Koreans believed that Hideyoshi's invasion would be just an extension of the previous pirate raids that had been repelled before.[100] As for the military situation in Joseon, the Korean scholar official Ryu Seong-ryong observed, "not one in a hundred [Korean generals] knew the methods of drilling soldiers":[101] rising in ranks depended far more on social connections than military knowledge.[102] Korean soldiers were disorganized, ill-trained, and ill-equipped,[102] and they had been used mostly in construction projects such as building castle walls.[103]

Japanese arquebuses of the Edo era were used by Japanese soldiers during Hideyoshi's invasions.

An illustration of an ampulliform Chinese fire-lance with a gunpowder charge shooting a blast of flame with lead pellets as coviative projectiles. The weapon was called the 'phalanx-charging fire-gourd'.

There were several defects with the organization of the Joseon-era Korean military defence system.[104] One example was a policy that stated that local officers could not individually respond to a foreign invasion outside of their jurisdiction until a higher ranking general, appointed by the King's court, arrived with a newly mobilized army.[104] This arrangement was highly inefficient since the nearby forces would remain stationary until the mobile border commander arrived on the scene and took control.[104] Secondly, as the appointed general often came from an outside region, he was likely to be unfamiliar with the natural environment, the available technology, and manpower of the invaded region.[104] Finally, as a main army was never maintained, new and ill-trained recruits conscripted during war constituted a significant part of the army.[104]

The Korean court managed to carry out some reforms, but they remain problematic. For example, the military training center established in 1589 in Gyeongsang province recruited mostly men either too young or too old to be good soldiers, augmented by some adventure-seeking aristocrats and slaves buying their freedom, because able-bodied men of the right age, targeted by the policy, had higher priorities such as farming and other economic activities, .[104]

The dominant form of the Korean fortresses was the "Sanseong", or the mountain fortress,[105] which consisted of a stone wall that continued around a mountain in a serpentine fashion.[98] These walls were poorly designed with little use of towers and cross-fire positions (usually seen in European fortifications), and were mostly low in height.[98] It was a wartime policy for these fortresses to serve as refuge castles and for everyone to evacuate to one, with those who failed to do so being assumed to be collaborators with the enemy; however, the policy never held any great effect because the fortresses were out of reach for most refugees.[98]

Hideyoshi mobilized his army at Nagoya Castle on Kyūshū, newly built for the sole purpose of housing the invasion forces and the reserves.[106] The first invasion consisted of nine divisions totaling 158,800 men, of which the last two of 21,500 were stationed as reserves in Tsushima and Iki respectively.[107] The Japanese used a total of 320,000 troops throughout the entire war.[97]

On the other side, Joseon maintained only a few military units with no field army, and its defense depended heavily on the mobilization of the citizen soldiers in case of emergency.[103] During the first invasion, Joseon Korea deployed a total of 84,500 regular troops throughout, assisted by 22,000 irregular volunteers.[108] Ming troops never numbered more than 60,000 troops in Korea at any point of the war.[109]

Since its introduction by the Portuguese traders on the island of Tanegashima in 1543,[110] the arquebus had become widely used in Japan.[111] While both Korea and China had also been introduced to firearms similar to the Portuguese arquebus, most were older models. The Korean soldiers' small arms were hand cannon with a simple mechanism and with either a gunstock or wooden shaft attached. After the Japanese diplomats presented the Korean court arquebuses as gifts, the Korean scholar-official Ryu Seong-ryong advocated the use of the new weapon, but the Korean court failed to realize its potency.[87] In contrast, the Japanese often deployed the arquebus in combination with archery in war.[112]

The Chinese also demonstrated massive use of rocket-propelled arrows, notably during the Siege of Pyongyang in January 1593. During siege actions, Chinese deployed rattan shields and iron pavises (large shields), reputed to be musket-proof.

The Japanese defeated successive Korean armies with a combination of muskets, spears, and swords. While muskets used by the Japanese were superior to Korean bows in terms of penetration and range[117] the former lacked the fire rate of the latter. Numerous battle accounts from the Annal of Joseon dynasty and various essays, diaries of Korean officials and commanders show that musket alone could not ensure victory. By employing both musket and arme blanche ("cold steel", swords, lances, spears, and the like), the Japanese were able to achieve success during the early phase of war. Indeed, the ferocious charge of Japanese troops with spears and swords were often more decisive than with muskets. This was because the Koreans were poorly trained in close combat, and lacked battlefield experience and discipline. Thus Korean soldiers were unable to hold their line against charging Japanese soldiers. The following words from a Korean military official named Shi-eon Lee to the Korean king discusses this weakness:

The King asked him [Shi-eon Lee], "You have already told me about the low accuracy of Japanese muskets. Why, then, are Korean armies having great problem with defeating them?"

[Shi-eon Lee] then answered, "The Korean soldiers cower before the enemy and flee for their lives even before they have engaged the enemy. As for the commanders, they seldom leave their positions because they fear that they might be executed for deserting. However, there is a limit to executing deserting soldiers since there are so many of them. Truly, the Japanese aren't good musketeers, but they advance so rapidly that they appear right in front of the Koreans in the time Koreans can shoot only two arrows. It is said that Koreans are good archers, but they seldom hit the targets when the enemy is too far away, and are too scared to shoot when the enemy is near because they fear Japanese swords. Archery often becomes useless because Koreans, fearing the Japanese arme blanche, can barely shoot. The Japanese are reputed to be good swordsmen, but it is possible for Koreans to draw swords and hold their ground. However, the Koreans seldom do this and merely run for their lives."[118]

The Koreans seldom employed field artillery, with cannon being mainly used in siege action and for defending castles. There were only very few instances of Koreans employing artillery in the field, with largely ineffective results.[119] Some irregular Korean units with government-supplied weapons fired explosive shells from mortars, but this occurred only in isolated instances.[119] The Chinese were more active in employing field artillery than the Koreans. One of the notable Chinese field guns was the "Great General Cannon", a large breech-loading cannon with a two-wheeled cart, shooting an iron ball weighing about 10 kilograms. The Japanese employed field artillery only where strategically advantageous in both siege and field warfare situations, often using captured pieces where available.

The Koreans actively deployed their cavalry divisions in action. But the terrain was often mountainous, which was not generally suitable for cavalry, the farmland tended to have many ditches, and it was often barren and lacked grass essential for feeding the horses. In addition, Japanese use of the arquebus at long range and in concentrated volleys negated any possibility of effective cavalry tactics.[115] Korean cavalrymen's primary weapons were bows, with swords and lances holding only subsidiary positions. Most of cavalry action for the Koreans took place in the Battle of Chungju at the beginning of the war, where they were outnumbered and wiped out by Japanese infantry.[120] Although the Japanese divisions also fielded cavalry they, usually dismounted when engaged in action, acting more as mounted infantry. While specialized firearms were used on horseback, most cavalrymen preferred the conventional yari (spear),[121] but its use was limited by the increasing use of firearms by the Koreans and Chinese.[122]

In contrast to the Japanese advantages on land, the Korea possessed an advantage at sea. Because of advanced artillery and shipbuilding technology, along with an extensive naval history against Japanese pirates, the Korean navies fielded highly advanced and formidable ships. By the time of the Japanese invasion, Korea employed the panokseon, a powerful galley-type ship armed with cannon that outranged most Japanese vessels. The Korean Navy used this naval superiority to disrupt the Japanese logistical network off the west coast of the Korean Peninsula. This advantage, however, did not affect Japan's ability to continuously reinforce its armies through the supply route from Tsushima in Japan to Busan in Korea, especially once Korean naval bases in the immediate area were neutralized by Japanese ground forces. The Korean navy led by Yi Sun-sin would withdraw and re-base in the northern border of Jeolla Province. While not able to entirely prevent reinforcement, the Korean navy continued to harass and inflict losses on the Japanese supply fleets throughout the duration of the war.

As virtually all Japanese ships in the first phase of the war lacked cannon artillery,[95] Korean ships outranged and bombarded Japanese ships with impunity outside the range of the Japanese muskets, arrows, and catapults.[95] When the Japanese attempted to outfit cannon to their ships,[123] their lightweight ship design prohibited using more than a few per vessel, and vessels usually lacked the firepower or range of their Korean counterparts.[124] In order to bolster their fleet, the Japanese considered employing two Portuguese galleons in the invasion.[125]

In addition to a lack of effective naval armament, most Japanese ships were modified merchant vessels more suited for transportation of troops and equipment than fielding artillery weapons.[95][126]

The Baekdudaegan mountain range runs down the length of the Korean peninsula. On either side of this "spine" is a narrow eastern coastal plain and a wider western coastal plain. These mountains are cut transversely by river valleys, the major rivers running east-west to drain into the Yellow Sea on the west coast. The major exception to this is the Nakdong River, with a course that runs north-south, joining the sea at Busan. Busan's harbour, its proximity to Japan, and its control of the route northwards along the Nakdong River valley made Busan the lynchpin of Japan's presence in Korea.

The combination of mountains and rivers creates a military geography of natural choke points, at mountain passes and river fords, which the Koreans reinforced with fortifications. It also creates a limited number of routes along which men and goods can most easily travel. Routes such as the Great Yeongnam Road, which joins the Han River valley to that of the Nakdong River valley by way of the Mungyeong Saejae pass, through the Sobaek Mountains, are the traditional invasion routes that armies in Korea have travelled. During the war these routes, especially in the mountains, were vulnerable to disruption when used for supplies.

Jeolla Province, the holding of which became critical in preventing the Japanese navy use of the western coast, is bounded on its east by the Sobaek Mountains, the southern spur of the Baekdudaegan, and in the north by the Geum River.

"Dongnaebu Sunjeoldo", a Korean painting from 1760 depicting the Battle of Dongnae

On April 13, 1592, the First Division of the Japanese invasion army, consisting of 7,000 men led by Konishi Yukinaga,[129] left Tsushima in the morning, and arrived at the port city of Busan in the evening.[130] Korean naval intelligence had detected the Japanese fleet, but Won Gyun, the Right Naval Commander of Gyeongsang, misidentified the fleet as trading vessels on a mission.[131] A later report of the arrival of an additional 100 Japanese vessels raised his suspicions, but the general did nothing about it.[131] Sō Yoshitoshi landed alone on the Busan shore to ask the Koreans for a safe passage to China for the last time; the Koreans refused, and Sō Yoshitoshi laid siege to the city. Konishi Yukinaga attacked the nearby fort of Dadaejin the next morning.[130] Japanese accounts claim that the battles dealt the Koreans complete annihilation (one claims 8,500 deaths, and another, 30,000 heads), while a Korean account claims that the Japanese themselves took significant losses before sacking the city.[132] On the morning of May 25, 1592, the First Division arrived at Dongnae eupseong.[132] The resulting Siege of Dongnae lasted twelve hours, killed 3,000, and resulted in Japanese victory.[133]

Katō Kiyomasa's Second Division landed in Busan on May 27, and Kuroda Nagamasa's Third Division, west of Nakdong, on May 28.[134] The Second Division took the abandoned city of Tongdo on May 28, and captured Kyongju on May 30.[134] The Third Division, upon landing, captured the nearby Kimhae castle by keeping the defenders under pressure with gunfire while building ramps up to the walls with bundles of crops.[135] By June 3, the Third Division captured Unsan, Changnyong, Hyonpung, and Songju.[135] Meanwhile, Konishi Yukinaga's First Division passed the Yangsan mountain fortress (captured on the night of the Battle of Dongnae, when its defenders fled after the Japanese scouting parties fired their arquebuses), and captured the Miryang castle on the afternoon of May 26.[136] The First Division secured the Cheongdo fortress in the next few days, and destroyed the city of Daegu.[136] By June 3, the First Division crossed the Nakdong River, and stopped at the Sonsan mountain.[136]

Upon receiving the news of the Japanese attacks, the Joseon government appointed General Yi Il as the mobile border commander, as was the established policy.[137] General Yi headed to Myongyong near the beginning of the strategically important Choryong pass to gather troops, but he had to travel further south to meet the troops assembled at the city of Daegu.[136] There, General Yi moved all troops back to Sangju, except for the survivors of the Battle of Dongnae who were to be stationed as a rearguard at the Choryong pass.[136] On April 25,[138] General Yi deployed a force of less than 1,000 men on two small hills to face the approaching First Division.[139] Assuming that the sight of rising smoke was from the burning of buildings by a nearby Japanese force, General Yi sent an officer to scout on horseback; however, as he neared a bridge, the officer was ambushed by Japanese musket fire from below the bridge, and was beheaded.[139] The Korean troops, watching him fall, were greatly demoralized.[139] Soon the Japanese began the Battle of Sangju with their arquebuses; the Koreans replied with their arrows, which fell short of their targets.[139] The Japanese forces, having been divided into three, attacked the Korean lines from both the front and the two flanks; the battle ended with General Yi Il's retreat and 700 Korean casualties.[139]

General Yi Il then planned to use the Choryong pass, the only path through the western end of the Sobaek mountain range, to check the Japanese advance.[139] However, another commander appointed by the Joseon government, Sin Rip, had arrived in the area with a cavalry division and moved 100,000 combined troops[140] to the Chungju fortress located above the Choryong pass.[141] Rather than face a siege, Sin Rip decided to fight a battle in the open fields of Tangeumdae, which he felt ideal for the deployment of his cavalry unit.[141] Since the cavalry consisted mostly of new recruits, however, Sin Rip was concerned that his troops may easily be tempted to flee the battle. As a result, he felt the need to trap his forces in the triangular area formed by the convergence of the Talcheon and Han rivers in the shape of a "Y".[141] This field, however, was dotted with flooded rice paddies and was generally not suitable for cavalry action.[141]

On June 5, 1592 the First Division of approximately 18,000 men led by Konishi Yukinaga left Sangju and reached an abandoned fortress at Mungyong by nightfall.[142] The next day, the First Division arrived at Tangumdae in the early afternoon where they faced the Korean cavalry unit at the Battle of Chungju. Konishi divided his forces into three and attacked with arquebuses from both flanks as well as the front.[142] The Korean arrows fell short of the Japanese troops, which were beyond their range, and General Sin's two charges failed to break the Japanese lines. General Sin then killed himself in the river, and the Koreans that tried to escape by the river either drowned or were decapitated by the pursuing Japanese.[142]

The Second Division led by Katō Kiyomasa arrived at Chungju, with the Third Division camped not far behind.[143] There, Katō expressed his anger against Konishi for not waiting at Busan as planned, and attempting to take all of the glory for himself; Nabeshima Naoshige then proposed a compromise of dividing the Japanese troops into two separate groups to follow two different routes to Hanseong (the capital and present-day Seoul) , and allowing Katō Kiyomasa to choose the route that the Second Division would take to reach Hanseong.[143] The two divisions began the race to capture Hanseong on June 8, and Katō took the shorter route across the Han River while Konishi went further upstream where smaller waters posed a lesser barrier.[143] Konishi arrived at Hanseong first on June 10 while the Second Division was halted at the river with no boats with which to cross.[143] The First Division found the castle undefended with its gates tightly locked, as King Seonjo had fled the day before.[144] The Japanese broke into a small floodgate, located in the castle wall, and opened the capital city's gate from within.[144] Katō's Second Division arrived at the capital the next day (having taken the same route as the First Division), and the Third and Fourth Divisions the day after.[144] Meanwhile, the Fifth, Sixth, Seventh, and Eighth Divisions had landed on Busan, with the Ninth Division kept in reserve on the island of Iki.[144]

Parts of Hanseong had already been looted and torched, including bureaus holding the slave records and weapons, and they were already abandoned by its inhabitants.[144] General Kim Myong-won, in charge of the defenses along the Han River, had retreated.[145] The King's subjects stole the animals in the royal stables and fled before him, leaving the King to rely on farm animals.[145] In every village, the King's party was met by inhabitants, lined up by the road, grieving that their King was abandoning them, and neglecting their duty of paying homage.[145] Parts of the southern shore of the Imjin River was burnt to deprive the Japanese troops of materials with which to make their crossing, and General Kim Myong-won deployed 12,000 troops at five points along the river.[145]

While the First Division rested in Hanseong (present-day Seoul), the Second Division began heading north, only to be delayed for two weeks by the Imjin River.[145] The Japanese sent a message to the Koreans on the other bank requesting them to open way to China, but the Koreans rejected this.[145] Afterwards, the Japanese commanders withdrew their main forces to the safety of the Paju fortress; the Koreans saw this as a retreat, and 13,000 Korean troops launched an attack at dawn against the remaining Japanese troops on the southern shore of the Imjin River.[145] The main Japanese body retaliated against the isolated Korean troops, and acquired their boats. The Korean troops under General Kim Myong-won retreated with heavy losses to the Kaesong fortress.[146]

With the Kaesong castle having been sacked shortly after General Kim Myong-won retreated to Pyeongyang,[146] the Japanese troops divided their objectives: the First Division would pursue the Korean king in Pyongan Province in the north (where Pyongyang is located); the Second Division would attack Hamgyong Province in the northeastern part of Korea; the Sixth Division would attack Jeolla Province at the southwestern tip of the peninsula; the Fourth Division would secure Gangwon Province in the mid-eastern part of the peninsula; and the Third, Fifth, Seventh, and Eighth Divisions would stabilize the following provinces respectively: Hwanghae Province (below Pyongan Province), Chungcheong Province (below Gyeonggi Province); Gyeongsang Province (in the southeast where the Japanese first had landed); and Gyeonggi Province (where the capital city is located).[147]

The First Division under Konishi Yukinaga proceeded northward, and sacked Pyongsan, Sohung, Pungsan, Hwangju, and Chunghwa along the way.[148] At Chunghwa, the Third Division under Kuroda Nagamasa joined the First, and continued to the city of Pyongyang located behind the Taedong River.[148] 10,000 Korean troops guarded the city against 30,000 Japanese[149] under various commanders including the Generals Yi Il and Kim Myong-won, and their defense preparations had assured that no boats were available for Japanese use.[148]

At night, the Koreans silently crossed the river and launched a successful surprise attack against the Japanese encampment.[148] However, this alerted the rest of the Japanese army, which attacked the rear of the Korean positions and destroyed the remaining reinforcements crossing the river.[150] Then the rest of the Korean troops retreated back to Pyongyang, and the Japanese troops gave up their pursuit of the Koreans to observe the way the Koreans crossed the river.[150]

The next day, using what they had learned from observing the retreating Korean troops, the Japanese began sending troops to the other shore over the shallow points in the river, in a systematic manner, and at this the Koreans abandoned the city overnight.[151] On July 20, 1592, the First and Third Divisions entered the deserted city of Pyongyang.[151][152] In the city, they managed to gather 100,000 tons of military supplies and grain.[152]

The Fourth Division under the command of Mōri Yoshinari set out eastward from the capital city of Hanseong (present-day Seoul) in July, and captured a series of fortresses along the eastern coast from Anbyon to Samcheok.[151] The division then turned inward to capture Jeongseon, Yeongwol, and Pyeongchang, and settled down at the provincial capital of Wonju.[151] There Mōri Yoshinari established a civil administration, systematized social ranks according to the Japanese model, and conducted land surveys.[151] Shimazu Yoshihiro, one of the generals in the Fourth Division, arrived at Gangwon late, due to the Umekita Rebellion, and finished the campaign by securing Chunchon.[153]

Katō Kiyomasa, leading the Second Division of more than 20,000 men, crossed the peninsula to Anbyon with a ten-day march, and swept north along the eastern coast.[153] Among the castles captured was Hamhung, the provincial capital of Hamgyong Province. There a part of the Second Division was assigned to defense and civil administration.[154]

The rest of the division, 10,000 men,[149] continued north, and fought a battle on August 23 against the southern and northern Hamgyong armies under the command of Yi Yong at Songjin (present-day Kimchaek).[154] A Korean cavalry division took advantage of the open field at Songjin, and pushed the Japanese forces into a grain storehouse.[154] There the Japanese barricaded themselves with bales of rice, and successfully repelled a formation charge from the Korean forces with their arquebuses.[154] While the Koreans planned to renew the battle in the morning, Katō Kiyomasa ambushed them at night; the Second Division completely surrounded the Korean forces with the exception of an opening leading to a swamp.[154] Those that fled were trapped and slaughtered in the swamp.[154]

Koreans who fled gave alarm to the other garrisons, allowing the Japanese troops to easily capture Kilchu, Myongchon, and Kyongsong.[154] The Second Division then turned inland through Puryong toward Hoeryong, where two Korean princes had taken refuge.[154] On August 30, 1592, the Second Division entered into Hoeryong where Katō Kiyomasa received the Korean princes and the provincial governor Yu Yong-rip, these having already been captured by the local inhabitants.[154] Shortly afterward, a Korean warrior band handed over the head of an anonymous Korean general, plus General Han Kuk-ham, tied up in ropes.[154]

Katō Kiyomasa then decided to attack a nearby Jurchen castle across the Tumen River in Manchuria to test his troops against the "barbarians", as the Koreans called the Jurchens ("Orangkae" in Korean and "Orangai" in Japanese – the Japanese derived both the word and the concept of the Jurchens as barbarians from the Koreans).[155] Kato's army of 8,000 was joined by 3,000 Koreans, at Hamgyong, because the Jurchens periodically raided across the border.[155] Soon the combined force sacked the castle, and camped near the border; after the Koreans left for home, the Japanese troops suffered a retaliatory assault from the Jurchens.[155] Katō Kiyomasa retreated with his forces to avoid heavy losses.[155] Because of this invasion, rising Jurchen leader Nurhachi offered military assistance to Joseon and Ming in the war. However, the offer was refused by both countries, particularly Joseon, saying that it would be disgraceful to accept assistance from the "Barbarians" to the north.

The Second Division continued east, capturing the fortresses of Jongseong, Onsong, Kyongwon, and Kyonghung, and finally arrived at Sosupo on the estuary of the Tumen River.[155] There the Japanese rested on the beach, and watched a nearby volcanic island on the horizon that they mistook as Mount Fuji.[155] After the tour, the Japanese continued their previous efforts to bureaucratize and administrate the province, and allowed several garrisons to be handled by the Koreans themselves.[156]

Having secured Pyeongyang, the Japanese planned to cross the Yalu River into Jurchen territory, and use the waters west of the Korean peninsula to supply the invasion.[157] However, Yi Sun-sin, who held the post of the Left Naval Commander of the Jeolla Province (which covers the western waters of Korea), successfully destroyed the Japanese ships transporting troops and supplies.[157] Japan, lacking enough arms and troops to carry on the invasion of China, changed the objective of the war to the occupation of Korea.[157]

When the Japanese troops landed at the port of Busan, Bak (also spelled Park) Hong, the Left Naval Commander of the Gyeongsang Province, destroyed his entire fleet, his base, and all armaments and provisions, and fled.[131]Won Gyun, the Right Naval Commander, also destroyed and abandoned his own base, and fled to Konyang with only four ships.[131] Thus there was no Korean naval activity around the Gyeongsang Province, and the surviving two, out of the four total fleets, were active only on the other (west) side of the peninsula.[131] Won Gyun later sent a message to Yi Sun-sin that he had fled to Konyang after being overwhelmed by the Japanese in a fight.[158] A messenger was sent by Yi Sun-sin to the nearby island of Namhae to give Yi's order for war preparations, only to find it pillaged and abandoned by its own inhabitants.[158] As soldiers began to flee secretly, Yi Sun-sin gave an order "to arrest the escapees" and had two of the fugitives brought back and beheaded; he then had their heads put out for display.[158] Yi Sun-sin's battles steadily affected the war and put significant strain on the sea lanes along the western Korean Peninsula supporting the Japanese advance.[159]

The Korean navy relied on a network of local fishermen and scouting boats to receive intelligence of the enemy movements.[159] On the dawn of June 13, 1592, Yi Sun-sin and Yi Eok-gi set sail with 24 panokseons, 15 small warships, and 46 boats (i.e. fishing boats), and arrived at the waters of Gyeongsang Province by sunset.[159]

The next day, the Jeolla fleet sailed to the arranged location where Won Gyun was supposed to meet them, and met the Yi Sun-sin on June 15. The augmented flotilla of 91 ships[163] then began circumnavigating Geoje Island, bound for Gadeok Island, but scouting vessels detected 50 Japanese vessels at Okpo harbor.[159] Upon sighting the approaching Korean fleet, some of the Japanese who had been busying themselves with plundering got back to their ships, and began to flee.[159] At this, the Korean fleet encircled the Japanese ships and finished them with artillery bombardments.[164] The Koreans spotted five more Japanese vessels that night, and destroyed four.[164] The next day, the Koreans approached 13 Japanese ships at Jeokjinpo.[164] In the same manner as the previous success at Okpo, the Korean fleet destroyed 11 Japanese ships – completing the Battle of Okpo without loss of a single ship.[164]

About three weeks after the Battle of Okpo,[165] Yi Sun-sin and Won Gyun sailed with a total of 26 ships (23 under Yi Sun-sin) toward the Bay of Sacheon after receiving an intelligence report of the Japanese presence.[166] Yi Sun-sin had left behind his fishing vessels that made up most of his fleet in favor of his newly completed turtle ship.[165]

A turtle ship is a vessel of a panokseon design with the removal of the elevated command post, the modification of the gunwales into curved walls, and the addition of a roof covered in iron spikes (and possibly hexagonal iron plates; this is disputed[160][161][162]).[167] Its walls contained a total of 36 cannon ports, and also openings, above the cannon, through which the ship's crew members could look out and fire their personal arms.[166] The design prevented enemies from boarding the ship and aiming at the personnel inside.[167] The ship was the fastest and most maneuverable warship in the East Asian theater, powered by two sails and 80 oarsmen taking turns on the ship's 16 oars.[126] No more than six turtle ships served throughout the entire war, and their primary role was to cut deep into the enemy lines, cause havoc with their cannon, and destroy the enemy flagship.[126]

On July 8, 1592, the fleet arrived at the Bay of Sacheon, where the outgoing tide prevented the Korean fleet from entering.[165] Therefore, Yi Sun-sin ordered the fleet to feign withdrawal, which the Japanese commander[who?] observed from his tent on a rock.[167] Then the Japanese hurriedly embarked their 12 ships and pursued the Korean fleet.[165] The Korean navy counterattacked, with the turtle ship in the front, and successfully destroyed all 12 ships.[165]

In response to the Korean navy's success, Toyotomi Hideyoshi recalled three commanders from land-based activities: Wakizaka Yasuharu, Kato Yoshiaki, and Kuki Yoshitaka.[168] They were the first commanders with naval responsibilities in the entirety of the Japanese invasion forces.[168] However, the commanders arrived in Busan nine days before Hideyoshi's order was actually issued, and assembled a squadron to counter the Korean navy.[168] Eventually Wakizaka completed his preparations, and his eagerness to win military honor pushed him to launch an attack against the Koreans without waiting for the other commanders to finish.[168]

The combined Korean navy of 53 ships[169] under the commands of Yi Sun-sin and Yi Ok-gi was carrying out a search-and-destroy operation because the Japanese troops on land were advancing into the Jeolla Province.[168] The Jeolla Province was the only Korean territory to be untouched by a major military action, and served as home for the three commanders and the only active Korean naval force.[168] The Korean navy considered it best to destroy naval support for the Japanese to reduce the effectiveness of the enemy ground troops.[168]

On August 13, 1592, the Korean fleet sailing from the Miruk Island at Dangpo received local intelligence that a large Japanese fleet was nearby.[168] The following morning, the Korean fleet spotted the Japanese fleet of 82 vessels anchored in the straits of Gyeonnaeryang.[168] Because of the narrowness of the strait and the hazard posed by the underwater rocks, Yi Sun-sin sent six ships to lure out 63 Japanese vessels into the wider sea,[169] and the Japanese fleet followed.[168] There the Japanese fleet was surrounded by the Korean fleet in a semicircular formation called "crane wing" by Yi Sun-sin.[168] With at least three turtle ships (two of which were newly completed) spearheading the clash against the Japanese fleet, the Korean vessels fired volleys of cannonballs into the Japanese formation.[168] Then the Korean ships engaged in a free-for-all battle with the Japanese ships, maintaining enough distance to prevent the Japanese from boarding; Yi Sun-sin permitted melee combats only against severely damaged Japanese ships.[168] The battle ended in a Korean victory, with Japanese losses of 59 ships – 47 destroyed and 12 captured.[170] Several Korean prisoners of war were rescued by the Korean soldiers throughout the fight. Wakisaka escaped due to the speed of his flagship.[170] When the news of the defeat at the Battle of Hansando reached Toyotomi Hideyoshi, he ordered that the Japanese invasion forces cease all naval operations.[168]

Yi Eok-gi with his fleet joined Yi Sun-sin and Won Gyun, and participated in a search for enemy vessels in the Gyonsang waters.[171] On July 13, the generals received intelligence that a group of Japanese ships including those that escaped from the Battle of Dangpo was resting in the Bay of Danghangpo.[171]

On August 16, 1592, Yi Sun-sin led their fleet to the harbor of Angolpo where 42 Japanese vessels were docked in battle of Angolpo.[168]

The Battle of Busan of 1592 (or more accurately, the Battle of Busanpo or Battle of Busan Bay) (釜山浦 海戰) was a naval engagement that took place on September 1, 1592. It was a Korean surprise attack on the Japanese fleet stationed at Busan, and its main objective was to regain Busan for the Joseon forces, which would have directly cut the supply lines of the Japanese army. The attempt was ultimately repulsed and the Korean fleet retreated. Japanese control of Busan was maintained, along with Japanese control of the sea lanes from Japan to Busan, until the end of the war. While a tactical victory for the Korean navy, the battle was a strategic victory for Japanese forces, who retained control of the Busan area and the vital supply lines back to Japan.

This can be translated as follows, "Yi Sun Shin and his fleet attacked Busan where the enemy forces stationed, but failed to defeat them. Since Japanese soldiers were often defeated in sea fights, they gathered in the fortress in Busan and Dongnae, which guarded the naval ships. Yi Sun Shin and Won Gyun attacked the Busan bay on vast numbers of ships, but the Japanese soldiers did not fight, and climbed to higher position and shot an arquebus. Thus Josen marines were unable to land then after burning 400 empty ships, Yi's fleet retreated. The Manho (Myriarch) of Rokdo (鹿島萬戶) Chong Woon (ko) was shot and died during the hard fighting, and Yi Sun Shin deeply regret the lost."

From the beginning of the war, the Koreans organized militias that they called "righteous armies" (의병) to resist the Japanese invasion.[173] These fighting bands were raised throughout the country, and participated in battles, guerilla raids, sieges, and the transportation and construction of wartime necessities.[174]

There were three main types of Korean "righteous army" militias during the war: the surviving and leaderless Korean regular soldiers, the patriotic yangbans (aristocrats) and commoners, and Buddhist monks.[174]

During the first invasion, Jeolla Province remained the only untouched area on the Korean peninsula.[174] In addition to the successful patrols of the sea by Yi Sun-sin, the activities of volunteer forces pressured the Japanese troops to avoid the province in favour of other priorities.[174]

Gwak Jae-u was a famous leader in the Korean militia movement, the first to form a resistance group against the Japanese invaders.[175] He was a land-owner in the town of Uiryong situated by the Nam River in the Gyeongsang Province. As the Korean regulars abandoned the town[174] and an attack seemed imminent, Gwak organized fifty townsmen; however the Third Division went from Changwon straight toward Songju.[175] When Gwak used abandoned government stores to supply his army, the Gyeongsang Province Governor Kim Su branded Gwak's group as rebels, and ordered that it be disbanded.[175] When Gwak asked for help from other landowners, and sent a direct appeal to the King, the governor sent troops against Gwak, in spite of having enough troubles already with the Japanese.[175] However, an official from the capital city then arrived to raise troops in the province, and, since the official lived nearby and actually knew him, he saved Gwak from troubles with the governor.[175]

Gwak Jae-u deployed his troops in guerilla warfare under the cover of the tall reeds on the union of the Nakdong and the Nam Rivers.[175] This strategy prevented Japanese forces from gaining easy access to Jeolla Province where Yi Sun-sin and his fleet were stationed.[175]

The Sixth Division under the command of Kobayakawa Takakage was in charge of conquering Jeolla Province.[175] The Sixth Division marched to Songju through the established Japanese route (i.e. the Third Division, above), and cut left to Geumsan in Chungcheong, which Kobayakawa secured as his starting base for his invasion of the province.[175]

Ankokuji Ekei, a former Buddhist monk made into a general due to his role in the negotiations between Mōri Terumoto and Toyotomi Hideyoshi, led the units of the Sixth Division charged with the invasion of Jeolla Province. The units began their march to Uiryong at Changwon, and arrived at the Nam River.[175] Ankokuji's scouts planted meters measuring the river's depths so that the entire squadron could cross the river; overnight, the Korean militiamen moved the meters into the deeper parts of the river.[175] As the Japanese troops began to cross, Gwak's militia ambushed them, and caused heavy losses for the Japanese.[175] In the end, to advance into Jeolla Province, Ankokuji's men had to try going north around the insecure grounds and within the security of the Japanese-garrisoned fortresses.[175] At Kaenyong, Ankokuji's target was changed to Gochang, to be taken with the aid of Kobayakawa Takakage.[175] However, the entire Jeolla campaign was then abandoned when Kim Myeon and his guerillas successfully ambushed Ankokuji's troops by firing arrows from hidden positions within the mountains.[175]

When the Japanese troops were advancing to Hanseong (present-day Seoul), Yi Kwang, the governor of Jeolla Province, attempted to check the Japanese progress by launching his army toward the capital city.[176] Upon hearing the news that the capital had already been sacked, the governor withdrew his army.[176] However, as the army grew in size to 50,000 men with the accumulation of several volunteer forces, Yi Kwang and the irregular commanders reconsidered their aim to reclaim Hanseong, and led the combined forces north to Suwon, 42 km (26 mi) south of Hanseong.[176][177] On June 4, an advance guard of 1,900 men attempted to take the nearby fortress at Yong-in, but the 600 Japanese defenders under Wakizaka Yasuharu avoided engagement with the Koreans until June 5, when the main Japanese troops came to relieve the fortress.[176][178] The Japanese troops counterattacked successfully against the Jeolla coalition, forcing the Koreans to abandon arms and retreat.[176]

Around the time of General Kwak's mobilization of his volunteer army in the Gyeongsang Province, Go Gyeong-myeong in Jeolla Province formed a volunteer force of 6,000 men.[176] Go then tried to combine his forces with another militia in the Chungchong Province, but upon crossing the provincial border he heard that Kobayakawa Takakage of the Sixth Division had launched an attack on Jeonju (the capital of Jeolla Province) from the mountain fortress at Geumsan. Go returned to his own territory.[176] Having joined forces with General Gwak Yong, Go then led his soldiers to Geumsan.[176] There, on July 10, the volunteer forces fought with a Japanese army retreating to Geumsan after a defeat at the Battle of Ichi two days earlier on July 8[179]

Jinju (진주) was a strategic stronghold that defended Kyongsang Province. The Japanese commanders knew that control of Jinju would mean easy access to the ricebelts of Jeolla Province. Accordingly, a large army under Hosokawa Tadaoki approached Jinju. Jinju was defended by Kim Simin (김시민), one of the better generals in Korea, commanding a Korean garrison of 3,000 men. Kim had recently acquired about 200 new arquebuses that were equal in strength to the Japanese guns. With the help of arquebuses, cannon, and mortars, the Koreans were able to drive the Japanese from Jeolla Province. The battle at Jinju is considered one of the greatest victories of Korea because it prevented the Japanese from entering Jeolla Province.

The Koreans could not hope to expel the Japanese from their land by themselves. Despite the various logistical and organizational difficulties suffered by the Japanese, Korea ultimately had to rely on the intervention of Ming China, to halt the advance of the first Japanese invasion.[180]

Korean Court historian Ryu Seong-ryong stated that the Korean naval victory stalled the entire strategy of the invaders by "cutting off one of the arms" with which Japan tried to envelop Korea, isolating Konishi Yukinaga's army at P'yongyang and securing Chinese waters from the feared Japanese attack, such that "the Celestial Army could come by land to the assistance" of Korea.[180]

Ming Dynasty Wanli Emperor

Viewing the crisis in Choson, the Ming Dynasty Wanli emperor and his court were initially filled with confusion and skepticism as to how their tributary could have been overrun so quickly.[181]

The Korean Court was at first hesitant to call for help from the Ming Dynasty, and began a withdrawal to Pyongyang.[182] The local governor at Liaodong eventually acted upon King Seonjo's request for aid following the capture of Pyongyang by sending a small force of 5,000 soldiers led by Zu Chengxun.[183] This cavalry force advanced almost unhindered and managed to enter Pyongyang, but was promptly and decisively defeated by the Japanese troops in the city. One of their leading generals, Shi Ru, was killed in this engagement. During the later half of 1592, the Ming sent investigation teams into Pyongyang to clarify the situation.[184] The Ming became fully aware of the situation and made the decision for a full reinforcement by September 1592.

By then it had become clear that this was a situation much more serious than something that could be handled by local forces. Thus the Ming Emperor mobilized and dispatched a larger force in January 1593 under the general Li Rusong and Imperial Superintendent Song Yingchang, the former being one of the sons of Ming dynasty's Liaodong military magistrate Li Chengliang and the latter being a bureaucratic officer (Ming military law stipulated that any military officer would have an accompanying bureaucrat appointed by the Imperial Court acting as the general's superior). According to the collection of letters left by Song Yingchang, the strength of the Ming army was around 40,000,[185] composed mostly of garrisons from the north, including around 3,000 men with experience against Japanese pirates under Qi Jiguang.

Thailand, a longtime faithful tributary state of the Chinese dynasties,[186][187] offered to directly attack Japan to intervene in Hideyoshi's plans, but Ming did not accept, instead ordering Thailand to attack Burma.[188]

On January 5, 1593, the Ming expeditionary army arrived outside Pyongyang accompanied by a group of Korean soldiers. Ming general Li Rusong was appointed the supreme commander of all armies in Korea. After initial attempts to negotiate with the Japanese defenders under Konishi Yukinaga broke down,[20] the two sides began skirmishing on the outskirts over the next couple of days, with the Li Rusong attempting to dislodge a Japanese garrison on the hills north of the city while Konishi Yukinaga attempted a night raid on the Ming camp.[20]

On the morning of January 8, Li ordered an all-out assault on three sides of the city; Japanese defenders were forced off the walls fairly quickly, and retreated to the citadel they built on the eastern portions of the city. The allies were unwilling to commit to a direct assault on the heavily defended fortification during the day. Instead they left an opening for the Japanese to rally while making preparations for a fire assault on their position at night. Japanese forces sallied out of the undefended eastern walls and made a run for Hanseong (Seoul), and they were hit with additional ambushes on the way back south and took heavy casualties.[189][190] Song YingChang's letters on March 1, 1593, described the battle in full to the Ming court. After their defeat, the Japanese shifted their strategy to hit-and-run tactics and ambushes. The use of gunpowder technology and street fighting contributed to the victory, which would permanently deter the invasion.[191]

Soon after retaking Pyongyang, Li also succeeded in retaking the major city of Kaesong on January 19, 1592,[192] and met only minor resistance from the Japanese defenders.

Overconfident with his recent success and possibly misled by false reports,[193] Li Rusong advanced towards the capital city of Hanseong (Seoul) with his allied army of 20,000[194] on January 21, 1592. On January 26, the force ran into an unexpected confrontation at Byeokjegwan with a large Japanese formation of about 30,000.

Initially, the scouting party of the group under Cha Da Sho and a Korean general confronted a small band of Japanese numbering no more than 600 men. The party overran them successfully but soon ran into a much larger host under Tachibana Muneshige, and retreated to a nearby hill to defend themselves.

Upon hearing of his scouting party's plight, Li decided to rush forward with the rest of his small host. He met up with his scouting party around noon, but by that time even more Japanese forces were converging on the area.

The Ming forces gradually retreated north while fighting off several waves of attacks. Li Rusong and many other generals personally fought in the brawl, and they sustained heavy casualties before they met up with the rest of their army toward the later portion of the day. The Japanese pursued the defeated Ming army back up the pass to its highest point, and after a few more hours of fighting[195][196][197][198] .[199] At that point, the Japanese gave up further attacks and both sides pulled back. Because the Ming suffered heavy casualties among their elite retinues, Li became reluctant to move aggressively for the remainder of the war.[200]

The Japanese invasion into Jeolla province was broken down and pushed back by General Gwon Yul at the hills of Ichiryeong, where outnumbered Koreans fought Japanese troops in Battle of Byeokjegwan and gained victory. Gwon Yul quickly advanced northwards, re-taking Suwon and then swung north toward Haengju where he would wait for the Chinese reinforcements. After he was informed that the Ming army under Li Rusong was pushed back at Byeokje, Gwon Yul decided to fortify Haengju.

Bolstered by the victory at Battle of Byeokjegwan, Katō and his army of 30,000 men advanced to the south of Hanseong to attack Haengju Fortress, an impressive mountain fortress that overlooked the surrounding area. An army of a few thousand led by Gwon Yul was garrisoned at the fortress, waiting for the Japanese. Katō believed his overwhelming army would destroy the Koreans and therefore ordered the Japanese soldiers to simply advance upon the steep slopes of Haengju with little planning. Gwon Yul answered the Japanese with fierce fire from the fortification using hwachas, rocks, handguns, and bows. Katō burned his dead and finally pulled his troops back.

The Battle of Haengju was an important victory for the Koreans, as it greatly improved the morale of the Korean army. The battle is celebrated today as one of the three most decisive Korean victories; the other two are the Siege of Jinju (1592) and the Battle of Hansando. Today, the site of Haengju fortress has a memorial built to honor Gwon Yul.

The two sides remained at a stalemate between the Kaesong to Hanseong line for the next couple of months, with both sides unable and unwilling to commit to further offensives. The Japanese lacked sufficient supplies to move north, and the defeat at Pyongyang had caused part of the Japanese leadership such as Konishi Yukinaga and Ishida Mitsunari to seriously consider negotiating with the Ming dynasty forces. This got them into a heated debate with other hawkish generals such as Kato Kiyomasa, and these conflicts would eventually have further implications following the war in Japan when the two sides became rivals in the Battle of Sekigahara.

The Ming forces had their own set of problems. Soon after arriving in Korea the Ming officials began to note the inadequate logistical supply from the Korean court. The records by Qian Shizhen noted that even after the siege of Pyongyang the Ming forces were already stalled for nearly a week due to the lack of supplies, before moving on to Kaesong.[202] As the time went on the situation only become more serious. When the weather warmed, the road condition in Korea also became terrible, as numerous letters from Song Yingchang and other Ming officers attest, which made resupplying from China itself also a tedious process.[203]

The Korean countryside was already devastated from the invasion when the Ming forces arrived, and in the heart of winter it was extremely difficult for the Koreans to muster sufficient supplies. Even though the court had assigned the majority of the men on hand to tackle the situation, their desire to reclaim their country along with the militarily inexperienced nature of many of their administrators resulted in their continually requests to the Ming forces to advance despite the situation. These events created an increasing level of distrust between the two sides.

Though by mid April 1593, faced with ever greater logistical pressure from a Korean naval blockade of Yi Sun-sin in addition to a Ming force special operation that managed to burn down a very significant portion of the Japanese grain storage,[204] the Japanese broke off talks and pulled out of Hanseong.

Unlike the First Siege of Jinju, the second siege resulted in a Japanese victory. The Korean garrison resisted for ten days, until a section of wall was breached by Japanese sappers, who had made use of an armoured cart called a "tortoise shell cart". The fortress was captured with the loss of the garrison commander, Hwang Jin, and all of his defenders and civilians.

There were two factors that triggered the Japanese to withdraw: first, a Chinese commando penetrated Hanseong (present-day Seoul) and burned storehouses at Yongsan, destroying most of what was left of the Japanese troops' depleted stock of food. Secondly, Shen Weijing made another appearance to conduct negotiations, and threatened the Japanese with an attack by 400,000 Chinese. The Japanese under Konishi and Kato, aware of their weak situation, agreed to withdraw to the Pusan area while the Chinese would withdraw back to China. A ceasefire was imposed, and a Ming emissary was sent to Japan to discuss peace terms.[205]

By May 18, 1594, all the Japanese soldiers had retreated to the area around Busan and many began to make their way back to Japan. The Ming government withdrew most of its expeditionary force, but kept 16,000 men on the Korean peninsula to guard the truce.

Once peace negotiations between China and Japan finally got underway, Chinese negotiators gave the Ming Emperor the mistaken impression that he was about to deal with a minor state that had been subdued by war. Furthermore, they conveyed the idea that the Japanese regent, Hideyoshi, was prepared to become his vassal. Under such conditions, the Chinese sought to resolve the issue in their favor by including Japan in their tributary system of foreign relations. They would establish Hideyoshi as king of Japan and grant him the privilege of formal tribute trade relations with the Ming dynasty.

In Japan, Hideyoshi's negotiators apparently led him to believe that China was suing for peace and was ready to accept him as their emperor. Thus, Hideyoshi issued the demands of a victor; first, a daughter of the Ming emperor must be sent to become the wife of the Japanese emperor; second, the southern provinces of Joseon must be ceded to Japan; third, normal trade relations between China and Japan must be restored; and fourth, a Joseon prince and several high-ranking government officials must be sent to Japan as hostages. Bargaining from such fundamentally different perspectives, there was no prospect whatsoever for success in the talks. Early in 1597, both sides resumed hostilities.[75]

During the period between the First and Second invasions, the Korean government had a chance to examine the reasons why they had been easily overrun by the Japanese. Ryu Seong-ryong, the Prime Minister, spoke out about the Korean disadvantages.

Ryu pointed out that Korean castle defenses were extremely weak, a fact which he had pointed out before the war. He noted how Korean castles had incomplete fortifications and walls that were too easy to scale. He also wanted cannons set up in the walls. Ryu proposed building strong towers with gun turrets for cannons. Besides castles, Ryu wanted to form a line of defenses in Korea. In this kind of defense, the enemy would have to scale many walls in order to reach Hanseong (Seoul).

Ryu also pointed out how efficient the Japanese army was, since it took them only one month to reach Hanseong, and how well organized they were. He noted how the Japanese moved their units in complex maneuvers, often weakening their enemy with the use of arquebuses, then attacking with melee weapons.

King Seonjo and the Korean court finally began to reform the military. In September 1593, the Military Training Agency (훈련도감, alternately translated as Military Training Command) was established. The agency carefully divided the army into units and companies. Within the companies were squads of archers, arquebusers, swordsmen, and spear infantry. The agency set up divisional units in each region of Korea and garrisoned battalions at castles. The agency, which originally had less than 80 troops, soon grew to about 10,000.

One of the most important changes was that both upper class citizens and slaves were subject to the draft. All males had to enter military service be trained and familiarized with weapons.

After the failed peace negotiations of the inter-war years, Hideyoshi launched the second invasion of Korea. One of the main strategic differences between the first and second invasions was that conquering China was no longer an explicit goal for the Japanese. Failing to gain a foothold during Katō Kiyomasa's Chinese campaign and the near complete withdrawal of the Japanese forces during the first invasion had established that the Korean peninsula was the more prudent and realistic objective.

Soon after the Chinese ambassadors had safely returned to China in 1597, Hideyoshi sent approximately 200 ships with an estimated 141,100 men under the overall command of Kobayakawa Hideaki.[99] Japan's second force arrived unopposed on the southern coast of Gyeongsang Province in 1596. However, the Japanese found that the Korean army was both better equipped and better prepared to deal with an invasion than several years prior.[103] In addition, upon hearing the news in China, the imperial court in Beijing appointed Yang Hao (楊鎬) as the supreme commander of an initial mobilization of 55,000 troops from various (and sometimes remote) provinces across China, such as Sichuan, Zhejiang, Huguang, Fujian, and Guangdong.[206] A naval force of 21,000 was included in the effort.[207]Ray Huang, a Chinese-American historian, estimated that the combined strength of the Chinese army and navy at the height of the second campaign was around 75,000.[208] Korean forces totaled approximately 30,000 with General Gwon Yul's army in Gong Mountain (공산; 公山) in Daegu, General Gwon Eung's (권응) troops in Gyeongju, Gwak Jae-u's soldiers in Changnyeong (창녕), Yi Bok-nam's (이복남) army in Naju, and Yi Si-yun's troops in Chungpungnyeong.

Initially the Japanese found limited success, being largely confined to Gyeongsang Province and only launching numerous raids to harass and weaken the Korean defenders. In the early Autumn of 1597, the Japanese began a more focused and sustained advance. The Japanese planned to attack Jeolla Province in the southwestern part of the peninsula and eventually occupy Jeonju, the provincial capital. Korean success in the Siege of Jinju in 1592 had mostly saved this area from devastation during the first invasion. Two Japanese armies, under Mōri Hidemoto and Ukita Hideie, began the assault in Busan and marched towards Jeonju, taking Sacheon and Changpyong along the way.

A naval battle. Close combat was very rare during Admiral Yi's operations.

The Korean navy was again to play a crucial part in the second invasion, as in the first, by hampering Japanese advances on land by harassing supply fleets at sea.[209] However, despite his previous successes, Yi Sun-sin was both demoted and jailed by King Seonjo, largely through infighting within the Korean court, but also due to his refusal to obey direct orders of the Korean court. This development allowed others within the court to further advance their personal agendas. Ultimately, Won Gyun was appointed in Yi Sun-sin's place at the head of the Korean navy.

After Won Gyun replaced Yi Sun-sin as head of the navy, he was quick to take action and justify his newly acquired position. He gathered the entire Korean fleet, which now had more than 100 ships outside of Yosu, to search for the Japanese. Without any previous preparations or planning, Won Gyun then had his entire fleet sail towards Busan.

After one day at sea, Won Gyun was informed of a large Japanese fleet near Busan. He decided to attack immediately, despite reports of exhaustion among the crew of the ship.

At the subsequent Battle of Chilcheollyang, Won Gyun was completely outmaneuvered by the Japanese in a surprise attack. His ships were overwhelmed by arquebus fire and the traditional Japanese boarding attacks, which largely resulted in the destruction of his entire fleet. But the defection before the battle of Bae Soel, an officer who did not submit to Won Gyun's leadership, kept thirteen panokseons out of the battle. These would form the entire fighting force of the Korean Navy during the immediately following months.

The Battle of Chilcheollyang was one of Japan's most decisive naval victories of the war. Won Gyun was himself killed by a Japanese garrison after he struggled ashore on an island after the destruction of his flagship. The victory allowed the Japanese navy to safely escort its troop ships and to support planned landing operations.[210]

After the disaster at Chilcheollyang, the allied defenses in the south began to quickly break down and the Japanese forces stormed into Jeolla province. The garrison of Namwon became their next key target.

Namwon was located fifty kilometres southeast of Jeonju. Correctly predicting a Japanese attack, a coalition force of 6,000 soldiers (including 3,000 Chinese troops under Yang Yuan and civilian volunteers) were prepared to fight the approaching Japanese forces.[211] The Japanese laid siege to the walls of the fortress with ladders and siege towers.[212] The two sides exchanged volleys with arquebuses and bows. Eventually the Japanese forces scaled the walls and sacked the fortress. According to Japanese commander Okochi Hidemoto, author of the Chosen Ki, the Siege of Namwon resulted in 3,726 casualties[213] among the Korean and Chinese forces.[214] The Korean forces and its leaders were almost entirely killed. Only Yang Yuan managed to sally out after the walls were breached, with a handful of men, to return to Hanseong (Seoul). He was later executed by the Ming court because of his defeat in battle.

Hwangseoksan Fortress consisted of extensive walls that circumscribed the Hwangseok Mountains and garrisoned thousands of soldiers led by generals Jo Jong-do and Gwak Jun. When Katō Kiyomasa laid siege to the mountain with a large army, the Koreans lost morale and retreated with 350 casualties. The successful siege did not, however, lead to a subsequent advance from beyond Gyeongsang Province.

Upon the start of the second invasion, the Ming emperor was furious about the entire debâcle of the peace talks and turned his wrath on many of its chief supporters; particularly Shi Xing, the Minister of War, who was removed from his position and jailed (he died several years later, in prison). The chief negotiator, Shen Weijing, was executed. Xing Jie was named the new minister of war and Yang Hao as the new chief superintendent (Jin Lue) of Korea; Xing Jie himself was also stationed in Korea for the remainder of the war. The Ming leadership quickly pulled in many units stationed near its border with Korea.

After the steady Japanese advances on land, they were planned to assault Hanseong (present-day Seoul) by late August or early September of 1597. However, the plans were foiled by a Ming defense around Jiksan (modern day Cheonan).

Forces under Kuroda Nagamasa formed the vanguard of the right army and marched toward Hanseong, which deeply disturbed the court at Hanseong. Several of the Ming generals stationed in Korea suggested to the court that they pull back their forces until they could gather more reinforcements, but the Ming administrators overruled their generals and ordered them to make a stand. Thus the chief commander of the Ming forces at the time, Ma Gui, sent out General Jie Sheng (解生) and three other generals with an elite cavalry force to confront the Japanese forces.

According to Korean records, the Ming forces ran into the vanguard forces under Kuroda around the area of Jiksan. On the first day, they beat back a small scouting party. On the second day, the two forces clashed in earnest, with the Japanese being beaten back.[215] Soon afterwards, a larger Japanese force showed up and the Ming forces also retreated. The Japanese army moved forward and occupied Gyeonggi Province.[216] This battle greatly relieved the Joseon and Ming courts and was seen as the beginning of a turnaround in the land campaign.[citation needed]

After the debacle in Chilcheollyang, King Seonjo immediately reinstated Yi Sun-sin. Yi Sun-sin quickly returned to Yeosu, where he found the majority of his navy destroyed. Yi re-organized the navy, now reduced to thirteen ships and approximately 200 men from the previous battle.[217] On September 16, 1597, in the Myeongnyang Strait, Yi Sun-sin encountered a large Japanese fleet of approximately 133 warships, with a further 200 logistical ships in support.[218] By making use of a narrow passage, Yi positioned his ships in a battle line that prevented the Japanese Navy from making use of their numerical superiority. The Battle of Myeongnyang resulted in a Korean victory, with Yi Sun-sin retaking the naval initiative.[219] The Battle of Myeongnyang is considered Yi Sun-sin's greatest battle, largely as a result of the disparity of numbers. Even after the victory, however, the Joseon navy was still outnumbered by the remaining Japanese navy, so Admiral Yi withdrew to the Yellow Sea to resupply his fleet and have more space for a mobile defense.[220] After the Korean navy withdrew, the Japanese navy made an incursion into the western coast of Korea, near some islands in Yeonggwang County. [221][222][223][224]

By late 1597, the Joseon and Ming allied forces achieved victory in Jiksan and pushed the Japanese further south. After the news of the loss at Myeongnyang, Katō Kiyomasa and his retreating army looted Gyeongju, the former capital of Unified Silla.

The Japanese forces sacked the city and many artifacts and temples were destroyed, most prominently, the Bulguksa, a Buddhist temple. Ming and Joseon forces continued to harass the Japanese forces, who then withdrew further south to Ulsan,[225] a harbor that had been an important Japanese trading post a century before, and which Katō had chosen as a strategic stronghold.

Yi Sun-sin's control of the areas around the Coast of Jeolla permitted no supply ships to reach the western side of the Korean Peninsula, into which many extensive tributaries merge. Without provisions and reinforcements, the Japanese forces were constrained to the coastal fortresses, known as wajō, that they still controlled. The advancing Ming forces attempted to take advantage of this situation by attacking Ulsan. This siege was the first major offensive from the Ming forces in the second phase of the war.

The effort of the Japanese garrison (about 7,000 men) of Ulsan was largely dedicated to its fortification in preparation for the expected attack. Katō Kiyomasa assigned command and defense of the base to Katō Yasumasa, Kuki Hirotaka, Asano Nagayoshi, and others before proceeding to Sosaengpo.[226] The Ming army's first assault on January 29, 1598, caught the Japanese Army unaware and still encamped, for the large part, outside Ulsan's unfinished walls.[227]

A total of around 36,000 troops with the help of singijeons and hwachas nearly succeeded in sacking the fortress, but reinforcements under the overall command of Mōri Hidemoto came across the river to aid the besieged fortress.[228] Although the Japanese garrison was desperately short of supplies, the Ming commander Ma Gui judged the situation to be going against the allies, because more and more Japanese forces began to arrive from the surrounding area and the allied forces were quickly becoming outnumbered.[229] Late one night, Ma Gui decided to order a general organized retreat of the allied forces, but soon confusion set in, and matters were further complicated by heavy rainfall and harassing attacks by the Japanese. The chief superintendent Yang Hao panicked and left hastily for Hanseong ahead of the army.[230][231][232]

The general retreat quickly turned into a chaotic rout, of which the Japanese took quick advantage by attacked the retreating Ming and Joseon forces.[233] The retreating Ming and Joseon forces had 20,000 losses.[234] The disaster was a heavy setback for Joseon, who would not be in a position to move on the Japanese position again for more than eight months.

After the Siege at Ulsan, the two sides remained in a stalemate for the next several months. Xing Jie decided that they would require further reinforcements to launch a final large offensive to permanently remove the Japanese presence on the Korean Peninsula.

Reinforcements from China began to pour in through most of mid-1598, with Chen Lin and Deng Zilong and their navy arriving in May. By September 1598, the Ming presence in Korea had swelled to 75,000 overall, by far the largest at any point in the war.

Xing Jie divided his forces into four groups, with Ma Gui leading the offensive against Ulsan yet again, Li Rumei leading the offensive against Sacheon, Chen Lin commanding the navy, and Liu Ting and Yi Sun-Sin coordinating a land-sea effort against Suncheon.

Just before they set out, however, news came that Li Rusong was killed by Mongolian tribesmen back in Liao Dong. Xing Jie decided to remove his emotionally weakened brother Li Rumei in favor of Dong Yi Yuan.

In June 1598, after Commander Konishi Yukinaga raised concerns about the supply situation and limited prospects for further territorial gains in the peninsula, 70,000 troops were withdrawn back to Japan, with only 60,000 left behind to guard the territory still under Japanese control. These forces were mostly Satsuma soldiers of the Shimazu clan under commanders Shimazu Yoshihiro and his son Tadatsune.[235] Kato Kiyomasa remained in command of the defenses of Ulsan while Konishi himself commanded the defenses at Suncheon.

The forces at Sacheon and Ulsan continued to be engaged in a military deadlock in the months that followed. In September 1598, 29,500 Ming and Joseon troops tried again to capture Ulsan Castle, but all their attempts were repulsed by the Japanese. The Ming and Joseon forces withdrew with heavy losses.[236][237]

The Chinese believed that Sacheon was crucial to their goal of retaking the lost castles in Korea and ordered a general attack. Although the Chinese made initial progress, the tide of battle turned when Japanese reinforcements attacked the rear of the Chinese Army and the Japanese soldiers inside the fortress sallied from the gates and counter-attacked.[238] The Chinese Ming forces retreated with 30,000 losses, with the Japanese in pursuit.[30] According to Chinese and Korean sources concerning the battle, the forces led by Dong Yi Yuan had breached the castle wall and were making progress in capturing the castle until a gunpowder accident caused an explosion in their camp, and the Japanese took advantage of the situation to rout the confused and weakened troops.[239]

At Suncheon, Konishi Yukinaga defended the castle with 13,700 Japanese soldiers.[240] A total of 50,000 Ming and Joseon troops tried to capture it, but their attempts were repulsed and they retreated with heavy losses. [241][242][243]

In the fall of 1598, following the successful Japanese defense at the battles of Sacheon, Ulsan, and Suncheon, the Ming, Joseon and Japanese forces were locked in a military stalemate in the south of the peninsula[29][244] After the death of Hideyoshi on September 18, 1598, the Council of Five Elders, in late October, issued orders for the withdrawal of all forces from Korea. Hideyoshi's death was kept a secret by the Council to preserve the morale of the army.

The Battle of Noryang Point was the final naval battle in the war. A Japanese Fleet of approximately 500 ships, under Shimazu Yoshihiro, was assembled and preparing to link up with the blockaded fleet under Konishi Yukinaga, and together withdraw via Pusan back to Japan.[245]

The Korean navy, under Yi Sun-sin discovered the Shimazu fleet anchored in the narrow straits of Noryang. Noting the narrow geography of the area, Ming general Chen Lin, who led Deng Zilong and Yi Sun-sin,[246] made a surprise attack against the Japanese fleet, under the cover of darkness on December 16, 1598, using cannon and fire arrows.

By dawn, nearly half of the Japanese fleet was scattered. During the pursuit of the remaining Japanese ships, both Yi Sun-sin and Deng Zilong were killed.[247] Despite suffering high casualties, in the end the battle was a tactical victory for the Korean forces and resulted in the loss of over half of the Japanese fleet.[248]

Strategically, however, the Japanese attained their objective by allowing Konishi Yukinaga, who was earlier blockaded by the Ming and Korean forces, to leave his fortress on December 16 with his men and withdraw unopposed by sailing through the southern end of Namhae Island, bypassing both the Noryang Strait and the battle. Konishi, Shimazu, Katō Kiyomasa and other Japanese generals of the Left Army congregated in Pusan and withdrew to Japan on December 21. The last ships sailed to Japan on December 24, bringing an end to seven years of war.

As Tsushima had suffered greatly from its loss of trade with Korea as a result of the invasions, Yoshitoshi of the Sō family, then dominant in Tsushima, undertook the lead in the peace negotiations by Japan. He sent four peace missions to Joseon in 1599 to normalize relations. The first three were captured and sent directly to Beijing by Chinese troops, but the fourth one, in 1601, successfully obtained from the Joseon court the promise of a normalizing of relations upon the return of remaining Joseon captives.[249] As Ming troops continued to be present in Korea following the withdrawal of Japanese forces, the major incentive for Joseon for the normalization of relations with Japan was the withdrawal of the Chinese soldiers from their territory. The Ming Chinese themselves were causing as much havoc as the Japanese had during the actual conflict, and their presence continued to strain the local economy and infrastructure.[249] In response to the Joseon request, Yoshitoshi promptly released several Joseon prisoners and between 1603 and 1604 helped the Joseon envoys to repatriate a further 3,000 by organizing negotiations at Kyoto with Tokugawa Ieyasu, by then the Shogun of Japan.[249]

In the continuation of the diplomatic talks toward peaceful relations, Joseon in 1606 expanded its conditions and demanded that the Shogun write a formal letter requesting peace, and to extradite the Japanese soldiers who had defiled the Joseon Royal Tombs near Hanseong (Seoul).[249] Realizing that the Shogunate would never agree to such a request, Yoshitoshi sent a forged letter and a group of criminals instead; the great need to expel the Ming soldiers pushed Joseon into accepting and to send an emissary in 1608.[249] The end result was a return of Joseon prisoners and the restoration of diplomatic and trade relations between the two countries.[250]

The Japanese invasions were Asia's first regional wars involving massed armies equipped with modern weapons.[251] The conflict saw the regular employment of Japanese armies of up to 200,000, Chinese armies of 80,000,[109] and the ongoing deployment of local Korean forces numbering in the hundreds of thousands.

The invasions also stood as a challenge to the existing Chinese world order on two levels:[252] the military, in which the war challenged Ming China's status as the supreme military power in East Asia, and the political, in which the war affirmed Chinese willingness to aid in the protection of its tributary states.[253]

Contrary to Toyotomi Hideyoshi's intentions, the cost of the Japanese invasions of Korea significantly weakened the Toyotomi clan's power in Japan. After Hideyoshi's death, his young son Toyotomi Hideyori became head of the Toyotomi clan. However, the losses suffered by varying daimyo during the campaign were a contributing factor to the imbalance of power in Japan after the war. As the western-based daimyo of Kyushu and western Honshu (partially by geographic convenience) contributed the majority of the forces used during the Korean conflict, it left the pro-Hideyoshi alliance weakened for the eventual struggle with the mostly eastern-backed forces of Tokugawa Ieyasu. Tokugawa would go on to unify Japan and establish himself as Shogun in 1603, following the decisive Battle of Sekigahara against a coalition of mostly western-based daimyo.[254]

Ming China also sustained a heavy financial burden for its role in defending Korea while also fighting several other conflicts in the same decade. The war also indirectly weakened China's position in Manchuria, which gave the fledgling Manchu chieftain Nurhachi an opportunity to expand his influence and territory. Nurhachi's expansions would culminate in the eventual collapse of the Ming Dynasty and the rise of the Qing Dynasty in 1644.[255] However, the sinocentric tributary system that the Ming had defended continued to be maintained by the Qing, and ultimately, the war resulted in a maintenance of the status quo – with the re-establishment of trade and the normalization of relations between all three parties.[256]

Given that the conflict was fought exclusively on Korean soil, Korea ultimately suffered the most damage of the three participants.[255] It lost a large portion of its military strength and civilian population, had numerous cultural heritage sites damaged or destroyed, and many of its technological advancements pillaged.[257] In many ways the invasions proved to be more devastating than any other event in the nation's history (even, arguably, more so than the Korean War).[256] The peninsula suffered a reduction of arable land to sixty-six percent of the prewar total,[258] greatly hurting Korea's mainly agricultural economy;[122] in the years that followed, famine, disease, and rebellions were widespread throughout Korea.[255] In Kyŏngsang Province alone 90% of the land under cultivation was destroyed.[259] Significant losses of historical archives, cultural and scientific artifacts (such as the Ja-gyuk-roowater clock[260]), and skilled artisans resulted in a waning of Korean science.[261] The main Korean royal palaces Gyeongbokgung, Changdeokgung, and Changgyeonggung were burned down, and Deoksugung was used as a temporary palace. The Baekjeong (Korean natives of the lowest social rank) took advantage of the lack of internal security brought on by invasion, and set fire to changnye (Korean government offices) in which census ledgers had been kept.[262] The destruction of land and census registers made fiscal recovery difficult since taxation and corvée labour were based on them. The government was forced to trade rank and titles in order to obtain napsok of grain,[259] and the Yangbang elite, which was exempt from household taxes, exploited the occasion to increase its landholdings, thereby further depriving the central government of taxes raised on property.[263]

The total military and civilian casualties, as estimated by the late 19th-century historian, Geo H. Jones, were one million,[264] and total combat casualties were estimated at between 250,000 and 300,000.[265] A total of over 185,000 Korean and over 29,000 Chinese troops were killed, and an estimated 50,000 to 60,000 captives were taken by the Japanese throughout the war.[266] Among those captured, a total of 7,500 were later returned to Korea through diplomatic means at the conclusion of the conflict.[267] A large portion of the remaining captives were sold to European traders — mainly Portuguese in Macau, who then resold them throughout Southeast Asia.[268][269]

The captives brought to Japan, including scholars, craftsmen, medicine makers, and gold smelters, provided Japan with many cultural and technological gains.[266] In the years that followed, Japanese pottery and art advanced and developed a significant similarity to their Korean counterparts.[159] Advances in other areas such as agriculture were also aided by technology and artisans acquired and captured during the invasions. Japanese typography advanced with the adoption of Chinese fonts.[270] Because Korean pottery was highly prized in Japan, many Japanese lords established pottery-producing kilns with captured Korean potters in Kyūshū and other parts of Japan.[271] The production of Arita porcelain in Japan began in 1616 at the town of Imari with the aid of Korean potters who had been enticed to relocate there after the war.[271]

As was typical in most prolonged military conflicts of the period, the war resulted in many instances of war brutality on all sides.

Japanese troops engaged in crimes against civilians in battles and often killed indiscriminately. Scorched earth policies were often employed: crops were burned, and farm animals were slaughtered to prevent their use by Joseon or Ming forces.[132] Outside of the main battles, raids to acquire foods and supply from civilians were common.[272] Captured prisoners were often mistreated or worked to near-death by starvation and neglect.[273] In following their battlefield practice at the time, the Japanese also collected the ears and noses of dead soldiers as proof of their exploits on the battlefield and as a record of casualty counts.[274] The high casualty rate of the Joseon and Ming forces, and the large number of ears collected during the campaign was enough to build a large mound near Hideyoshi's Great Buddha, called the Mimizuka, or the "Mound of Ears."[275]

Korean armies were also known to forcefully acquire food and supplies from civilians, both on an individual and organized level.[136] Korean bandits and highwaymen also took advantage of the chaos during the war to form raiding parties and rob other Koreans.[276]

The Ming forces arriving in support of Joseon were often no better than the Japanese in the amount of destruction they caused and the degree of the crimes they committed.[249] Ming forces often did not distinguish between loyal Joseon civilians and Japanese collaborators.[277] In one notable case, the civilians of Namhae, who the Chinese General Chen Lin labelled as Japanese collaborators, were killed without justification.[277] After the immediate Japanese military threat was neutralized, the Joseon desire for the Ming Armies to quickly withdraw from Korean territory was a contributing factor to the pace of the eventual peace resolution.[249]

The war left significant legacies in all three countries. In the context of Japanese imperialism, the invasions are seen as the first Japanese attempt to become a global power.[256] The partial occupation of Korea developed the Japanese concept that Korea belonged within Japan's sphere of influence, and the Japanese leaders of the late 19th and the early 20th centuries used the 1592–1597 invasions to reinforce the justification for their 20th century annexation of Korea.[278]

In China, the war was used politically to inspire nationalistic resistance against Japanese imperialism during the 20th century.[256] In Chinese academia, historians list the war as one of the Wanli Emperor's "Three Great Punitive Campaigns."[256] Contemporary Chinese historians often use the campaigns as an example of the friendship the two nations shared.[citation needed]

In Korea, the war is a historic foundation of Korean nationalism and, as in China, inspired and was used politically to instigate nationalistic resistance against Japanese imperialism during the 20th century. Korea gained several national heroes during the conflict, such as Admiral Yi Sun-sin.[256] Even today, anti-Japanese sentiment in Korea can be traced as far back as the Japanese invasions in 1592, although the principle cause is rooted in more recent events, particularly the hardships suffered by Koreans during the Japanese occupation of Korea from 1910 through 1945.

Despite great interest in the war in East Asia,[279] the Japanese invasions of Korea are not widely known in the West.[280] Historian Stephen Turnbull attributes this to titles such as Hideyoshi's Invasions of Korea (merely an extended part of Toyotomi Hideyoshi's biography) and the Japanese invasions of Korea (simply a larger repeat of the Japanese wokou pirate raids) absent the distinction as a "war."[94] Many history textbooks treat the war with only a few lines of mention, and with the exception of Samurai Invasion: Japan's Korean War 1592–98 by Turnbull, no complete academic studies on the subject exists in English,[281] although both Murdoch and Sansom covered the topic in some detail in their general historical surveys of Japan, A History of Japan (1903) and A History of Japan (1958), respectively.

Note: All websites are listed here independently from the References section.

^ abLee, Kenneth (January 1, 1997). Korea and East Asia: The Story of a Phoenix. Greenwood Publishing Group. p. 108. Retrieved March 26, 2015. "Thus the Korea–Japan War of 1592–1598 came to a conclusion, with the Japanese totally defeated and in full-scale retreat. The Korean victory did not come easily."

^ abHistory of the Ming chapter 322 Japan "前後七載 (For seven years)，喪師數十萬 (Hundreds of thousands of soldiers were killed)，糜餉數百萬 (Millions of cost of war was spent)，中朝與朝鮮迄無勝算 (There were no chances of victory in China and Korea)，至關白死兵禍始休。 (By Hideyoshi's death ended the war.)"

^Cite error: The named reference Turnbull.2C_Stephen._2002.2C_pp._221. was invoked but never defined (see the help page).

^Cite error: The named reference Turnbull.2C_Stephen._2002.2C_p._229. was invoked but never defined (see the help page).

^Perez, Louis (2013). Japan At War: An Encyclopedia. Santa Barbara, California: ABC-CLIO. p. 141. "Korean and Chinese forces were able to hold off the Japanese troops and confine the fighting to the southern provinces."

^ abTurnbull, Stephen. 2002, p. 134, "(Korean) war minister Yi Hang-bok pointed out that assistance from China was the only way Korea could survive."

^Turnbull, Stephen (Nov 20, 2012). The Samurai Invasion of Korea 1592–98. Osprey Publishing. p. 17. Retrieved March 25, 2015. "His naval victories were to prove decisive in the Japanese defeat, although Yi was to die during his final battle in 1598."

^Perez, Louis (2013). Japan At War: An Encyclopedia. Santa Barbara, California: ABC-CLIO. p. 140."Just as a complete Japanese victory appeared imminent, Admiral Yi entered the war and quickly turned the tide."

^Perez, Louis (2013). Japan At War: An Encyclopedia. Santa Barbara, California: ABC-CLIO. pp. 140–141."Yi's successes gave Korea complete control of the sea lanes around the peninsula, and the Korean navy was able to intercept most of the supplies and communications between Japan and Korea"

^Lewis, James (December 5, 2014). The East Asian War, 1592–1598: International Relations, Violence and Memory. Routledge. pp. 160–161. Retrieved May 2, 2015. "The righteous armies that appeared in 1592 smashed the local rule distributed across Korea's eight provinces by the Japanese military. The righteous army activities were one of the most important factors for the frustration of the Toyotomi regime's ambition to subjugate Ming China and extend dominion over Korea."

^Perez, Louis (2013). Japan at War: An Encyclopedia. ABC-CLIO. p. 140. "A series of victories quickly followed, culminating in the destruction of a Japanese fleet carrying reinforcements... Yi burned or sank more than 120 warships and destroyed most of a convoy carrying 100,000 Japanese soldiers."

^Lewis, James (December 5, 2014). The East Asian War, 1592–1598: International Relations, Violence and Memory. Routledge. p. 277. Retrieved May 30, 2015. "Ming's participation, however, was motivated more by self-defense than by the intention to help Chosŏn. At the time, Japan had explicitly declared its plans to "borrow a road to enter the Ming." Because of this, Ming feared for the security of Liaodong, and eventually came to worry about the threat to Beijing from a Chosŏn occupied by the Japanese army."

^Lewis, James (December 5, 2014). The East Asian War, 1592-1598: International Relations, Violence and Memory. Routledge. pp. 160–161. Retrieved May 2, 2015. "The righteous armies that appeared in 1592 smashed the local rule distributed across Korea's eight provinces by the Japanese military. The righteous army activities were one of the most important factors for the frustration of the Toyotomi regime's ambition to subjugate Ming China and extend dominion over Korea."

^Swope, Kenneth. "Beyond Turtleboats: Siege Accounts from Hideyoshi's Second Invasion of Korea, 1597–1598"(PDF). Sungkyun Journal of East Asian Studies: 58. Retrieved 2013-09-07. At this point in 1593, the war entered a stalemate during which intrigues and negotiations failed to produce a settlement. As the suzerain of Joseon Korea, Ming China exercised tight control over the Koreans during the war. At the same time, Ming China negotiated bilaterally with Japan while often ignoring the wishes of the Korean government.

^Lewis, James B. Frontier Contact Between Choson Korea and Tokugawa Japan. Routledge. ISBN9781135795986. Retrieved 20 July 2016. "Tribute trade was the oldest and most important component of the trade structure, not for its volume or content, but for its symbolism. Japanese brought items to "offer" to Korea and received in exchange "gifts" of higher value, since Korea was a greater land receiving supplicants. Koreans viewed tribute trade as a "burden" and a favor extended to needy islanders; the significance was diplomatic not economic."

^The Book of Corrections: Reflections on the National Crisis during the Japanese Invasion of Korea, 1592–1598. By Sôngnyong Yu. Translated by Choi Byonghyon. Berkeley: Institute of East Asian Studies, University of California, 2002. xi, 249 pp. James B. Lewis. The Journal of Asian Studies, Volume 63, Issue 02, May 2004, pp 524–526. doi:10.1017/S0021911804001378, Published online by Cambridge University Press February 26, 2007.

^Turnbull, Stephen (Nov 20, 2012). The Samurai Invasion of Korea 1592–98. Osprey Publishing. p. 63. Retrieved May 2, 2015. "The despondent Chinese general Li Rusong resolved to return to the fray when he heard of the triumph at Haengju, and Chinese troops began to move south towards Seoul once again."

^Statements in "The records of the Eastern Expedition" by Qian Shizhen

^Various letters by Song Yingchang, including the letter to Li Rusong on February 10, 1593 stating "今糧草未敷泥濘難進"

^Huang, Ray, "The Lung-ch'ing and Wan-li Reigns, 1567–1620." in The Cambridge History of China. Vol. 7, The Ming Dynasty, 1368–1644, Part I, edited by Denis Twitchett and John Farbank. Cambridge University Press, 1988, p. 572.

^Huang, Ray, "The Lung-ch'ing and Wan-li Reigns, 1567–1620." in The Cambridge History of Chani. Vol. 7, The Ming Dynasty, 1368–1644, Part I, edited by Denis Twitchett and John Farbank. Cambridge University Press, 1988, p. 572.

^This refers to a record of the number of noses collected, as samurai during the Korean campaign were paid according to how many noses they collected in contrast to the more traditional practice of collecting heads, which were impractical to transport back to the Japanese mainland.

^The History of the Ming chapter 239 朝鮮再用師，詔一元隸總督邢玠麾下，參贊軍事。尋代李如梅為禦倭總兵官。時兵分四路。一元由中路，禦石曼子於泗州，先拔晉州，下望晉，乘勝濟江，連毀永春、昆陽二寨。賊退保泗州老營，攻下之，遊擊盧得功陣歿。前逼新寨。寨三面臨江，一面通陸，引海為濠，海艘泊寨下千計，築金海、固城為左右翼。一元分馬步夾攻。步兵遊擊彭信古用大棓擊寨，碎其數處。眾軍進逼賊濠，毀其柵。忽營中炮裂，煙焰漲天。賊乘勢沖擊，固城援賊亦至。騎兵諸將先奔，一元亦還晉州。事聞，詔斬遊擊馬呈文、郝三聘，落信古等職，充為事官；一元亦奪宮保，貶秩三等。

Swope, Kenneth M. "Crouching Tigers, Secret Weapons: Military Technology Employed During the Sino-Japanese-Korean War, 1592–1598", The Journal of Military History pp. 69 (January 2005): pp. 11–42. (C) Society for Military History.

Swope, Kenneth M. "Deceit, Disguise, and Dependence: China, Japan, and the Future of the Tributary System, 1592–1596". The International History Review, XXIV. 4: December 2002, pp. 757–1,008.

Villiers, John. "SILK AND SILVER: MACAU, MANILA AND TRADE IN THE CHINA SEAS IN THE SIXTEENTH CENTURY" (A lecture delivered to the Hong Kong Branch of the Royal Asiatic Society at the Hong Kong Club. 10 June 1980). The HKUL Digital Initiatives